The Oxford Thesaurus An A-Z Dictionary of Synonyms - err v.

1) be wrong, be in error, be mistaken, be inaccurate, be incorrect, be in the wrong, go wrong, go astray, make a mistake, miscalculate, (make a) blunder, bungle, botch, fumble, muff, make a mess of, make a faux pas, mess up , US bobble; Colloq goof (up) , slip (up) , drop a clanger, foul up, Brit drop a brick, blot one's copybook, Slang screw up, Brit boob, Taboo slang fuck up: The referee erred in ruling that the ball was out. 2) misbehave, sin, transgress, trespass, lapse, fall, do wrong: She has erred many times in her long life.